Efectividad de la vacuna contra la gripe

https://theconversation.com/the-flu-vaccine-is-being-oversold-its-not-that-effective-97688?fbclid=IwAR2e4DB1T1AQWi-e51teBs21unDh89M3Z3LpjgXpeERGGv5mB4nJAeDXMBE